The Top 3 Most Common PV System Failures
While Australia may have been slower to embrace solar than some of our European neighbours, we've certainly made up for lost time. With over 3.6 million rooftop solar systems now installed across the country, we’re leading the charge in renewable energy adoption. And rightly so, because we have some of the highest solar exposure and UV intensity in the world!
But with this surge comes a new challenge—keeping these systems running efficiently and safely. Like any electrical setup, solar PV (Photovoltaic) systems aren’t immune to faults. This is your electrical system that converts sunlight into electricity; thus, it needs to be fault-free for optimal performance.
So, here's a look at the top three most common PV system failures, how to spot them early, and what you can do to prevent costly breakdowns.
1. Inverter Failures
Think of your solar inverter as the brain of your PV system. It’s responsible for converting the DC electricity generated by your panels into usable AC power for your home or business. When it fails, the entire system takes a hit.
Common Inverter Issues
Inverters are complex and work hard, so it’s no surprise they’re often the first component to fail.
Common issues include:
- Overheating, especially if installed in direct sun or poorly ventilated areas
- Software faults or firmware glitches
- Wear and tear over time, especially with older string inverters nearing the end of their 10–15-year lifespan
Signs of Inverter Failure
Most modern systems now alert you via error codes or warning lights on the display. However, you may also notice a drop in solar energy production, or even no energy being fed into your system.
Prevention Tips
- Install the inverter in a shaded, well-ventilated spot
- Schedule regular servicing to keep it dust-free and check connections
- Stay on top of firmware updates for smart inverters
- Check warranty length and conditions—some inverters only have 5-year warranties, but extended coverage is often available
Like most things, prevention is the best protection. Regular maintenance, at least twice a year, is your best strategy for ensuring the longevity of your solar panels.
2. Panel Degradation or Physical Damage
As you can imagine, with solar panels up on the roof, they are exposed to the elements. While that's the whole point (in terms of sun exposure), they take a beating from the wind, rain, and the epic storms we get in Sydney and Wollongong. While they’re designed to last 20–25 years, gradual degradation or sudden damage impacts how much clean power is generated from your solar energy system.
Common Causes
- Harsh weather like hailstorms, strong winds, or intense UV exposure can wear panels down
- Manufacturing defects, though these are usually spotted early
- Installation errors, such as poor mounting or loose wiring, can stress the panels and frames
Effects on Performance
Over time, solar panels naturally degrade, reducing their ability to convert sunlight into electricity. Most panels lose around 0.5% efficiency per year, but damage can accelerate that decline, especially if microcracks form (quite common) or moisture enters the panel layers (also common).
Visual Signs of Damage
- Cracks in the glass surface
- Burn or hot spot marks on the solar cells
- Yellowing or discolouration on the solar modules
- Delamination (where layers begin to peel or bubble)
Prevention Tips
- Choose reputable brands with strong warranties
- Schedule routine inspections, particularly after storms
- Install protective netting or guards if your roof is exposed to falling branches or debris
- Hire a tree surgeon to cut the deadwood from trees overhanging and shading your solar panels
- Avoid walking on panels, an obvious one, which can cause hidden fractures
Showing your panels some TLC means more efficient energy output over the long run, which results in longer-lasting savings.
3. Wiring and Connection Issues
One of the most common causes of system failure we see is that the wiring was either not properly set up during installation, or it hasn't been well maintained since. This is what keeps everything running smoothly and safely, and unfortunately, there are still some unqualified installers out there not wiring systems correctly. Connection issues are almost always human-made.
Common Causes
- Loose or poorly connected wiring during installation
- Corrosion from exposure to moisture, especially in coastal areas
- Rodents chewing through cables (a surprisingly common issue)
- UV degradation of exposed wiring over time
Impact on Performance and Safety
Wiring faults lead to intermittent system shutdowns, reduced power output, and even complete system failure. Worse still, poor connections, especially at the isolator switches or DC connectors, pose a serious fire risk, which is why wiring is one of the most critical components we monitor.
Common Failure Points
- DC isolators, which are required by Australian standards, but are often exposed to weather
- Connector plugs, particularly if mismatched or not securely fastened
- Cable junctions, where strain or poor sealing can allow water ingress
Prevention Tips
- Always use a Clean Energy Council (CEC) accredited installer
- Schedule periodic system testing and thermographic inspections to detect hot spots or loose joints
- Protect cables with conduit and weatherproof covers
- Act quickly if you notice flickering power, strange system behaviour, or visible damage
In terms of wiring, out of sight shouldn’t mean out of mind. Good wiring is one of the most important aspects for a safe, efficient solar system.
Preventative Maintenance and Inspections
On the subject of prevention, maintenance is hands-down the best way to keep your PV system running efficiently and avoid unexpected breakdowns. It's no coincidence that our customers with the least PV system failures are the ones who schedule regular maintenance, as well as carry out their own DIY maintenance. Even if your system appears to be performing well, underlying issues can slowly affect output.
Why Maintenance Matters
A well-maintained solar system not only maximises your return on investment, it also assures the longevity of your components and helps you catch small issues before they become costly failures. Think of it like servicing your car: a little attention annually or biannually can save you a lot down the line.
How Often Should You Service Your System?
It’s recommended that homeowners schedule a professional solar inspection at least once every 12 to 24 months. For commercial systems or properties in harsher environments such as coastal or bushfire-prone areas, annual servicing is a smarter choice.
Need a Check-Up?
If it’s been a while since your last inspection (or you’ve never had one), book a solar service with Easther Electrical today. It’s a small investment that keeps your solar system running safe, smart, and strong for years to come. Most importantly, it gives you peace of mind that you're protecting and future-proofing your return on investment.
Frequently Asked Questions
What are the faults in PV systems?
Common faults include inverter failure, potential induced degradation of panels, and wiring or connection issues that reduce performance or solar panel system safety.
What are major problems with photovoltaic cells?
Major problems include microcracks, delamination, and UV-related wear that reduce energy output of your solar power system over time.
What is the most common fault ground on a solar system?
The most common ground fault of solar installations is insulation breakdown, which can cause leakage currents and trigger inverter shutdowns for safety.